Servocontrol for dual hydraulic systems

Claim 2

A hydraulic actuator system comprising, in combination, first and second fluid chambers, a piston mounted in each of said fluid chambers, means connecting said pistons for equal, simultaneous movement within their respective fluid chambers, a first source of pressure fluid, first conduit means connecting said first source to said first fluid chamber, a second source of pressure fluid, second conduit means connecting said second source to said second fluid chamber, a servo valve assembly operatively connected in said first conduit means and providing controlled parallel fluid circuits between said first source and said first fluid chamber, said servo valve assembly also being operatively connected in said second conduit means and providing controlled parallel fluid circuits between said second source and second fluid chamber, and signal input means operating said servo valve assembly to control the flow of pressurized fluid through each of said fluid circuits simultaneously.

Claim 3

The hydraulic actuator system defined in claim 1 wherein said servo valve assembly comprises first and second servo valves each operatively connected in said first conduit means and in said second conduit means, said first and said second servo valves cooperating to provide said parallel circuits between said first source and said first fluid chamber and between said second source and said second fluid chamber.

Claim 4

The hydraulic actuator system defined in claim 2 wherein said signal input means comprises an input assembly normally applying equal operating loads to said first and said second servo valves to thereby synchronize operation of the two valves.

Claim 5

The hydraulic actuator system defined in claim 3 wherein said signal input means further comprises means for operating one of said servo valves independently of operation of the other of said servo valves in the event said other servo valve becomes inoperable.

Claim 6

The hydraulic actuator system as defined in claim 4 wherein said first and said second servo valves are positioned in side-by-side relation, and said signal input means comprises a whiffletree operatively connected to each of said servo valves for operation thereof.

Claim 7

The hydraulic actuator system as defined in claim 4 wherein said signal input means further comprises a prestressed resilient connector assembly connected to each of said servo valves, said connector assembly being deformable by either of said servo valves only upon said valves encountering a substantial increase in resistance to operation.

Claim 8

A hydraulic actuator system comprising, in combination, first and second fLuid chambers, a pair of pistons mounted one in each of said fluid chambers, an output member, means connecting said pistons to said output member for simultaneous movement therewith, a first source of pressure fluid, first conduit means connecting said first source to said first fluid chamber, a second source of pressure fluid, second conduit means connecting said second source to said second fluid chamber, first servo valve means connected in said first conduit means and providing a controlled circuit for pressure fluid between said first source and said first fluid chamber and connected in said second conduit means and providing a controlled circuit for pressure fluid between said second source and said second fluid chamber, second servo valve means connected in said first conduit means in parallel with said first servo valve and providing a second controlled circuit for pressure fluid between said first source and said first fluid chamber and in said conduit means in parallel with said first servo valve means and providing second controlled circuit for pressure fluid between said second source and said second fluid chamber, signal input means operating said first and said second valve means, said signal input means including means synchronizing operation of said first and said second servo valve means to simultaneously direct pressurized fluid through each of said controlled circuits.

Claim 9

A hydraulic actuator system comprising, in combination, first and second fLuid chambers, a pair of pistons mounted one in each of said fluid chambers, an output member, means connecting said pistons to said output member for simultaneous movement therewith, a first source of pressure fluid, first conduit means connecting said first source to said first fluid chamber, a second source of pressure fluid, second conduit means connecting said second source to said second fluid chamber, first servo valve means connected in said first conduit means and providing a controlled circuit for pressure fluid between said first source and said first fluid chamber and connected in said second conduit means and providing a controlled circuit for pressure fluid between said second source and said second fluid chamber, second servo valve means connected in said first conduit means in parallel with said first servo valve and providing a second controlled circuit for pressure fluid between said first source and said first fluid chamber and in said conduit means in parallel with said first servo valve means and providing second controlled circuit for pressure fluid between said second source and said second fluid chamber, signal input means operating said first and said second valve means, said signal input means including means synchronizing operation of said first and said second servo valve means to simultaneously direct pressurized fluid through each of said controlled circuits.

Claim 10

The hydraulic actuator system defined in claim 7 wherein said first and said second servo valve means each comprise a valve spool moveably mounted within a valve body, a plurality of ports in said valve body including first inlet and outlet ports connected to said first source, second inlet and outlet ports connected to said second source, a first pair of distribution ports connected to said first fluid chamber, and a second pair of distribution ports connected to said second fluid chamber, said valve spool being moveable within said valve body to simultaneously control flow through said first inlet and outlet ports and said first distribution ports between said first source and said first fluid chamber and through said second inlet and outlet ports and said second distribution ports between said second source and said second fluid chamber.

Claim 11

The hydraulic actuator system as defined in claim 8 wherein said valve spools in said first and said second servo valves are slidably mounted within axial bores in said valve body to control the flow of pressure fluid through said inlet and outlet ports and said distribution ports.

Claim 12

The hydraulic actuator system defined in claim 9 wherein said valve spools are slidably mounted in coaxial relation in a single bore in a common valve body.

Claim 13

The hydraulic actuator system defined in claim 9 wherein said input means comprises linkage means independently connected to said valve spools in said first and said second servo valves for simultaneous movement, said linkage means including means moving one of said valve spools independently of movement of the other valve spool in the event of said other valve spool requiring excessive operating force.

Claim 14

The hydraulic actuator system defined in claim 11 wherein said means independently connecting said valve spools include prestressed resilient connecting means.